Populations of Dendroctonus frontalis mass attack pine trees throughout the southeastern United States, overwhelming the resin defense system and killing the trees. Many factors including variation in host resistance, predator population abundance, and intraspecific competition influence the fates of these local populations. For example, trees with high resin defenses require more beetles to overwhelm the system. This may lead to high numbers of beetles within the bark of that tree. The result is intense intraspecific competition among the attacking adult beetles for space in the phloem to construct oviposition gallery, and subsequent competition among the developing larvae for nutrients. The adult beetles can sense the within tree population, and exhibit multiple behaviours to limit competition. One such behaviour involves exiting the beetle-packed tree and finding a more suitable host. This behaviour, while beneficial in limiting intraspecific competition leaves the beetles vulnerable to predation. Tree defenses, host selection patterns, and population abundances of predators and D. frontalis were studied during 2001-2002. Preliminary results link reproductive success of beetles at the tree level to host selection and intraspecific competition, as well as local predator population abundances.
Species 1: Coleoptera scolytidae Dendroctonus frontalis (southern pine beetle)
Keywords: tree defenses, population dynamics
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